ardinal Bernard F. Law yesterday urged a gathering of antiabortion activists to patiently endure shouts and barbs from their opponents - then had to put his advice into practice when a heckler criticized his handling of the sexual abuse scandal.

''Ours cannot be the clenched fist. Ours cannot be the raised voice,'' Law told a crowd of about 2,000 people gathered on Boston Common for the annual Respect Life Walk to Aid Mothers and Children, sponsored by Massachusetts Citizens for Life.

''The cardinal is a liar. Bernard Law is a hypocrite,'' a man at the edge of the crowd shouted.

The heckler, who had earlier been part of a group of three dozen protesters outside of the Cathedral of the Holy Cross, was confronted by several members of the antiabortion group and was escorted off the Common by a Boston police officer. After the speech, Law said he was not upset by the interruption.

''You do what you need to do,'' he said. ''I am doing what I need to do, and I suppose that heckler is doing what he thinks he needs to do. I think people were pretty focused on what I had to say. And in this forum, I think people are pretty accustomed to having a point-counterpoint.''

Massachusetts Citizens for Life board member June Newman of Braintree, who served as the master of ceremonies for the event, said people at the rally were generally supportive of Law, who has long been a vocal advocate of the church's positions against abortion, euthanasia, and the death penalty.

''He is committed to the sanctity of life,'' said Newman. ''We have to respect that and not digress into other areas.''

Fall River Bishop Sean Patrick O'Malley, who has been credited for instituting pioneering policies on clergy sexual abuse and has been named by Pope John Paul II to lead the diocese of Palm Beach, Fla., praised Law for attending the event.

''He comes here every year and I think he didn't want to stay away, even knowing that there would be people who object to his presence,'' O'Malley said. ''But his stand on the life issues has been very constant, and I think he wanted to make his presence felt here today.''

Law's decision to attend was criticized by some, including another protester at the Cathedral, Boston College professor Richard Rowland, 71, of Newton. ''The cardinal's refusal to bring closure'' to the clergy sexual abuse issue ''hurts everything that's high on his agenda,'' Rowland said.

After an hour of speeches, gospel songs, and prayers, attendees who were raising money for various antiabortion causes marched onto Beacon Street, led by O'Malley. Law has traditionally participated in the walk, but he left yesterday after the speeches to attend another event in Needham, aides said.

On their way off the Common, the marchers passed through about 75 slogan-shouting abortion-rights supporters holding a counterdemonstration. ''There is a prochoice majority in Massachusetts, and we wanted to make sure that our presence was known today,'' said Laksmi Anantnarayan of the Somerville-based group The Abortion Access Project.

Law was also preparing yesterday to review new child protection rules drafted by the Cardinal's Commission for the Protection of Children, a 15-person advisory board he appointed after the clergy sex abuse scandal broke in January.

The commission is expected to meet today and then give its final policy recommendations to Law, who praised its work yesterday as ''very conscientious and helpful.'' He said the recommendations will be studied from the viewpoint of church theology and canon law, then turned into guidelines replacing the existing policy.

Material from the Associated Press was used in this report. Ralph Ranalli can be reached at rranalli@globe.com.